嵌入式系统基于STM32F103VC开发板设计音乐播放器

/** ****************************************************************************** * @file system_stm32f10x.c * @author MCD Application Team * @version V3.5.0 * @date 11-March-2011 * @brief CMSIS Cortex-M3 Device Peripheral Access Layer System Source File. * * 1. This file provides two functions and one global variable to be called from * user application: * - SystemInit(): Setups the system clock (System clock source, PLL Multiplier * factors, AHB/APBx prescalers and Flash settings). * This function is called at startup just after reset and * before branch to main program. This call is made inside * the "startup_stm32f10x_xx.s" file. * * - SystemCoreClock variable: Contains the core clock (HCLK), it can be used * by the user application to setup the SysTick * timer or configure other parameters. * * - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must * be called whenever the core clock is changed * during program execution. * * 2. After each device reset the HSI (8 MHz) is used as system clock source. * Then SystemInit() function is called, in "startup_stm32f10x_xx.s" file, to * configure the system clock before to branch to main program. * * 3. If the system clock source selected by user fails to startup, the SystemInit() * function will do nothing and HSI still used as system clock source. User can * add some code to deal with this issue inside the SetSysClock() function. * * 4. The default value of HSE crystal is set to 8 MHz (or 25 MHz, depedning on * the product used), refer to "HSE_VALUE" define in "stm32f10x.h" file. * When HSE is used as system clock source, directly or through PLL, and you * are using different crystal you have to adapt the HSE value to your own * configuration. * ****************************************************************************** * @attention * * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS. * * <h2><center>&copy; COPYRIGHT 2011 STMicroelectronics</center></h2> ****************************************************************************** */ /** @addtogroup CMSIS * @{ */ /** @addtogroup stm32f10x_system * @{ */ /** @addtogroup STM32F10x_System_Private_Includes * @{ */ #include "stm32f10x.h" /** * @} */ /** @addtogroup STM32F10x_System_Private_TypesDefinitions * @{ */ /** * @} */ /** @addtogroup STM32F10x_System_Private_Defines * @{ */ /*!< Uncomment the line corresponding to the desired System clock (SYSCLK) frequency (after reset the HSI is used as SYSCLK source) IMPORTANT NOTE: ============== 1. After each device reset the HSI is used as System clock source. 2. Please make sure that the selected System clock doesn't exceed your device's maximum frequency. 3. If none of the define below is enabled, the HSI is used as System clock source. 4. The System clock configuration functions provided within this file assume that: - For Low, Medium and High density Value line devices an external 8MHz crystal is used to drive the System clock. - For Low, Medium and High density devices an external 8MHz crystal is used to drive the System clock. - For Connectivity line devices an external 25MHz crystal is used to drive the System clock. If you are using different crystal you have to adapt those functions accordingly. */ #if defined (STM32F10X_LD_VL) || (defined STM32F10X_MD_VL) || (defined STM32F10X_HD_VL) /* #define SYSCLK_FREQ_HSE HSE_VALUE */ #define SYSCLK_FREQ_24MHz 24000000 #else /* #define SYSCLK_FREQ_HSE HSE_VALUE */ /* #define SYSCLK_FREQ_24MHz 24000000 */ /* #define SYSCLK_FREQ_36MHz 36000000 */ /* #define SYSCLK_FREQ_48MHz 48000000 */ /* #define SYSCLK_FREQ_56MHz 56000000 */ #define SYSCLK_FREQ_72MHz 72000000 #endif /*!< Uncomment the following line if you need to use external SRAM mounted on STM3210E-EVAL board (STM32 High density and XL-density devices) or on STM32100E-EVAL board (STM32 High-density value line devices) as data memory */ #if defined (STM32F10X_HD) || (defined STM32F10X_XL) || (defined STM32F10X_HD_VL) /* #define DATA_IN_ExtSRAM */ #endif /*!< Uncomment the following line if you need to relocate your vector Table in Internal SRAM. */ /* #define VECT_TAB_SRAM */ #define VECT_TAB_OFFSET 0x0 /*!< Vector Table base offset field. This value must be a multiple of 0x200. */ /** * @} */ /** @addtogroup STM32F10x_System_Private_Macros * @{ */ /** * @} */ /** @addtogroup STM32F10x_System_Private_Variables * @{ */ /******************************************************************************* * Clock Definitions *******************************************************************************/ #ifdef SYSCLK_FREQ_HSE uint32_t SystemCoreClock = SYSCLK_FREQ_HSE; /*!< System Clock Frequency (Core Clock) */ #elif defined SYSCLK_FREQ_24MHz uint32_t SystemCoreClock = SYSCLK_FREQ_24MHz; /*!< System Clock Frequency (Core Clock) */ #elif defined SYSCLK_FREQ_36MHz uint32_t SystemCoreClock = SYSCLK_FREQ_36MHz; /*!< System Clock Frequency (Core Clock) */ #elif defined SYSCLK_FREQ_48MHz uint32_t SystemCoreClock = SYSCLK_FREQ_48MHz; /*!< System Clock Frequency (Core Clock) */ #elif defined SYSCLK_FREQ_56MHz uint32_t SystemCoreClock = SYSCLK_FREQ_56MHz; /*!< System Clock Frequency (Core Clock) */ #elif defined SYSCLK_FREQ_72MHz uint32_t SystemCoreClock = SYSCLK_FREQ_72MHz; /*!< System Clock Frequency (Core Clock) */ #else /*!< HSI Selected as System Clock source */ uint32_t SystemCoreClock = HSI_VALUE; /*!< System Clock Frequency (Core Clock) */ #endif __I uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}; /** * @} */ /** @addtogroup STM32F10x_System_Private_FunctionPrototypes * @{ */ static void SetSysClock(void); #ifdef SYSCLK_FREQ_HSE static void SetSysClockToHSE(void); #elif defined SYSCLK_FREQ_24MHz static void SetSysClockTo24(void); #elif defined SYSCLK_FREQ_36MHz static void SetSysClockTo36(void); #elif defined SYSCLK_FREQ_48MHz static void SetSysClockTo48(void); #elif defined SYSCLK_FREQ_56MHz static void SetSysClockTo56(void); #elif defined SYSCLK_FREQ_72MHz static void SetSysClockTo72(void); #endif #ifdef DATA_IN_ExtSRAM static void SystemInit_ExtMemCtl(void); #endif /* DATA_IN_ExtSRAM */ /** * @} */ /** @addtogroup STM32F10x_System_Private_Functions * @{ */ /** * @brief Setup the microcontroller system * Initialize the Embedded Flash Interface, the PLL and update the * SystemCoreClock variable. * @note This function should be used only after reset. * @param None * @retval None */ void SystemInit (void) { /* Reset the RCC clock configuration to the default reset state(for debug purpose) */ /* Set HSION bit *